A mobile device such as a smartphone or tablet includes a plurality of physical buttons for different functions. For example, a power button is for turning on and off the mobile device, a volume up button is for increasing the volume, and a volume down button is for decreasing the volume. However, a user's finger must move to different locations to control the different buttons, causing operational inconvenience. In addition, the plurality of buttons have a plurality of components, causing difficulties in manufacturing and assembling the mobile device.